Conventional stroke font drawing is carried out by placing vector data on pixels and determining the brightness value of each of the pixels. In this case, in order to display smooth lines, antialiasing for setting up two or more levels of brightness values used as intermediate colors and drawing characters is used frequently. However, there is a case in which when drawing a low resolution font, such an intermediate color is recognized as a blot. To solve this problem, according to a conventional grid fitting method, by paying an attention to the vertical and horizontal segments (referred to as segments from here on) of a line segment, the segments are corrected to optimal positions on pixels to draw a sharp line segment. At the time of correcting the segments, the coordinates of the segments are selected in such a way that characters are not flattened due to an adjacency between the segments (for example, refer to patent reference 1).